Aerosol generation in public restrooms

Jesse H Schreck; Masoud Jahandar Lashaki; Javad Hashemi; Manhar Dhanak; Siddhartha Verma

doi:10.1063/5.0040310

Aerosol generation in public restrooms

Phys Fluids (1994). 2021 Mar;33(3):033320. doi: 10.1063/5.0040310. Epub 2021 Mar 22.

Authors

Jesse H Schreck¹, Masoud Jahandar Lashaki², Javad Hashemi¹, Manhar Dhanak¹, Siddhartha Verma¹

Affiliations

¹ Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida 33431, USA.
² Department of Civil, Environmental and Geomatics Engineering, Florida Atlantic University, Boca Raton, Florida 33431, USA.

Abstract

Aerosolized droplets play a central role in the transmission of various infectious diseases, including Legionnaire's disease, gastroenteritis-causing norovirus, and most recently COVID-19. Respiratory droplets are known to be the most prominent source of transmission for COVID-19; however, alternative routes may exist given the discovery of small numbers of viable viruses in urine and stool samples. Flushing biomatter can lead to the aerosolization of micro-organisms; thus, there is a likelihood that bioaerosols generated in public restrooms may pose a concern for the transmission of COVID-19, especially since these areas are relatively confined, experience heavy foot traffic, and may suffer from inadequate ventilation. To quantify the extent of aerosolization, we measure the size and number of droplets generated by flushing toilets and urinals in a public restroom. The results indicate that the particular designs tested in the study generate a large number of droplets in the size range $0.3 μ m$ - $3 μ m$ , which can reach heights of at least 1.52 m. Covering the toilet reduced aerosol levels but did not eliminate them completely, suggesting that aerosolized droplets escaped through small gaps between the cover and the seat. In addition to consistent increases in aerosol levels immediately after flushing, there was a notable rise in ambient aerosol levels due to the accumulation of droplets from multiple flushes conducted during the tests. This highlights the need for incorporating adequate ventilation in the design and operation of public spaces, which can help prevent aerosol accumulation in high occupancy areas and mitigate the risk of airborne disease transmission.